const fp = require('lodash/fp')

// 数据
// horsepower 马力， dollar_value 价格， in_stock 库存
const cars = [
  {name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true},
  {name: 'Spyker C12 Zagato', horsepower: 650, dollar_value: 648000, in_stock: false},
  {name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false},
  {name: 'Audi R8', horsepower: 525, dollar_value: 114200, in_stock: false},
  {name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true},
  {name: 'Pagani Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false},
]


// 练习1

let isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last)


// 练习2

let getFirstProp = fp.flowRight(fp.prop('name'), fp.first)


// 练习3

let _average = function (xs) {
  return fp.reduce(fp.add, 0, xs) / xs.length
} // <- 无需改动
const prop = val => val.dollar_value
let averageDollarValue = fp.flowRight(_average, fp.map(prop))


// 练习4

let _underScore = fp.replace(/\W+/g, '_') // <-- 无需改动，并在sanitizeNames中使用它
let sanitizeNames = fp.map(fp.flowRight(_underScore, fp.toLower))

